The present disclosure is a deep well sample collection apparatus. It is a sample apparatus that enables collection of a specified volume of sample for use in deep well monitoring. In one aspect, it can be used to test the purity of an acquifier. It also can be used to test for leakage of industrial or nuclear waste around a large plant facility. A shallow sample collection apparatus is set forth in co-pending patent application Ser. No. 795,147 which was filed on Feb. 7, 1997. That sample collection apparatus is adapted for sample measurement at shallow depths. Most of the samples that are important in that type of equipment are found just below the surface. Common depths are just a few feet and typically not greater than about 50 feet. By contrast, this disclosure enables the installation of the equipment at depths measured in hundreds or indeed in thousands of feet. In testing a water acquifier for instance, the acquifier may surface in a certain geographic area and slope away to an underground location at lateral distances from it. As greater depths are accomplished, the acquifier might have an overburden of five thousand feet. As a rough rule of thumb, the water pressure is approximately one pound per square inch (psi) for about 26 or 27 inches of water; therefore, a depth of five thousand feet will provide a water pressure of about 2,300 to 2,400 psi. It is difficult to get a test sample off the bottom of that kind of deep well.
The present disclosure sets forth a deep well system which enables sample collection. In particular, it Utilizes a vacuum operated chamber deployed in a deep well which collects and removes a sample in the manner set forth in the above-mentioned co-pending application. That, however, is not enough structure in the sense that it can provide a sample when overburdened at great depths. As the depth increases, great depth and the heavy standing columns of water prevent proper operation and may interfere with sample collection. Moreover, as the depth increases, prevailing pressures at the equipment set forth in the foregoing disclosure are increased. The present apparatus enables sample collection in cooperation with a second pump assure sample delivery and proper turnover in the deep well. This equipment is advantageous for a number of reasons. Among others, this equipment has the advantage of operating at great depths while yet obtaining a sample from the water sampling well. Moreover, as flow goes in and out of the region, the water sample is interchanged and gathering of samples is obtained while trapping of the remaining portion of water in the deep well is avoided. So to speak, water flows by percolation down stream in an acquifier. The acquifier will receive rain at its exposed portion, thereby enabling the water to flow down the slope to greater depths. This migration is carried out through the percolating sand formation and also flows through the deep well. The well is cased, conveniently with a three inch or four inch plastic pipe with a number of perforations in it at different depths. This enables flow of water into and out of the percolating pipe. The perforations permit such an interchange.
The present equipment is especially useful in that it flushes the bottom region of the pipe which lines the well. For example, the well may be cased with four thousand feet of pipe. In the preferred form, it is perforated at many locations except near the bottom. The bottom most portion of about five to ten feet is left without perforations.
So that water does not stagnate at that area, the present apparatus stirs and replaces that water by expelling a portion of it separate from the sample which is taken. This assures that fresh sample collection occurs.
The present apparatus is therefore summarized as including a vacuum operated sample measuring and delivery system. More than that, it also includes and features a bottom located sample input mechanism having a positive displacement pump which assures volumetric turnover in the region of the sample collection pump.
One version is an electric powered positive displacement water pump assisting a vacuum pump. It operates with a packer sleeve which is expanded to isolate a position of the well. The packer sleeve isolates the bottom portion of the well. When the packer inflates the well portion is isolated so that the sample in that area is properly collected and that any remaining portion of the water in that area is expelled for the moment so that turnover can be accomplished.